Ti Plasmid

 

Ti Plasmid

The Tumour inducing or Ti plasmid is present in the bacterium Agrobacterium tumifaciens.

It is widely used now as a cloning vector to deliver desirable genes to the host plant to get transgenic plants. The main characteristics of Ti plasmid are:

  • Size of the plasmid is ~ 250kbp
  • There are different kinds of Ti plasmids based on the different genes they possess, which code for different opines, e.g. leucinopine, nopaline, octopine, etc.
  • It is a pathogenic species to many dicotyledonous plants. It causes crown gall disease in plants.
  • It contains one or more T-DNA region
  • Agrobacterium tumifaciens has an ability to transform the normal cells to tumour cells by inserting a DNA piece known as T DNA and it starts producing chemicals, that are required by the bacterium
  • After inserting the desired gene into Ti plasmid, it loses its pathogenic ability but is still able to insert the desired gene into the plant cell
  • It contains vir or virulence genes, which transfer T-DNA region to plant cells and gets integrated into the plant genome
  • Ti plasmid can be modified as per the requirement to insert the desired genes
  • Agrobacterium tumifaciens is called “nature’s genetic engineer”

Ti Plasmid

Comments

Post a Comment

Popular posts from this blog

What is EcoRI?

Image
  What is EcoRI? EcoRI is a restriction enzyme or restriction endonuclease. It cuts the DNA double helix at a specific site. This restriction enzyme was first isolated from  E.coli.  These restriction enzymes derive their names from the organisms where it was first isolated from. Similarly, another restriction enzyme was named HindIII as it was isolated from  Haemophilus influenzae. Here Eco refers to  Escherichia.coli.  R is for the strain RY13 and I (one) as it was the first enzyme to be isolated from the given strain. So EcoRI is pronounced as Eco-R-One. Restriction enzymes present in bacteria are a defence mechanism to protect against bacteriophage. Due to methylation, bacterial DNA remains unaffected. Read on to know more about EcoRI. Key Features of EcoRI EcoRI was discovered in Herbert Boyer’s lab. It is a type II restriction enzyme, which cuts specifically at the restriction site having 5’-GAATTC-3’ sequence. It cuts the DNA at a specific site forming sticky ends. Restriction s
Read more

pBR322 Plasmid

Image
  pBR322 Plasmid The main characteristics of pBR322 are: Restriction sites:  BamH I, Hind III, Sal I, Pvu I, Pvu II, Pst I, EcoR I, Cla I Selectable marker:  antibiotic resistance genes for ampicillin (amp R ) and tetracycline (tet R ) ORI:  the origin of replication ROP:  It codes for proteins, which are involved in the process of replication of plasmid Different antibiotic resistance genes act as a restriction site and to ligate foreign DNA and for the selection of transformants. The gene, where the foreign DNA is inserted becomes inactive. Alternative selectable marker:  Mostly these have an ability to produce some colour after reacting with a chromogenic substance. The alternative markers are used for the ease of differentiating recombinants from non-recombinants, e.g. gene coding for β-galactosidase. When a foreign gene is inserted between the gene coding for β-galactosidase ,  the recombinant cell does not produce the enzyme β-galactosidase due to inactivation of the gene. In the
Read more
  In higher classes, you will come to know that all living phenomena are due to underlying interactions. Properties of tissues are not present in the constituent cells but arise as a result of Interactions among the constituent cells. Similarly, properties of cellular organelles are not present in the molecular constituents of the organelle but arise as a result of interactions among the molecular components comprising the organelle. These interactions result in emergent properties at a higher level of organisation. This phenomenon is true in the hierarchy of organisational complexity at all levels. Therefore, we can say that living organisms are self-replicating, evolving and self-regulating interactive systems capable of responding to external stimuli. Biology is the story of life on earth. Biology is the story of evolution of living organisms on earth. All living organisms - present, past and future, are linked to one another by the sharing of the common genetic material, but to var
Read more